In-house electrode production for maximum precision
In sinker EDM, the electrode largely determines the accuracy and surface quality of the final result. That is why Tumag designs and produces sinker EDM electrodes in-house. From our facility in Turnhout, we combine CAD/CAM engineering, specialised graphite machining and EDM process knowledge into one controlled process.
What is a sinker EDM electrode?
A sinker EDM electrode is a precisely shaped tool used to create a form in a workpiece through spark erosion. The electrode determines the final geometry and is therefore crucial for dimensional accuracy, shape stability and surface quality. You can compare it to a milling cutter for a machinist: without the correct electrode, an accurate and reproducible sinker EDM result is not possible.
Electrodes as the basis for precise sinker EDM
In sinker EDM, the shape of the electrode is transferred to the workpiece through controlled spark erosion. Any deviation in the electrode can therefore translate into the final geometry. Especially for complex cavities, sharp details, deep forms or precise mould components, the quality of the electrode is crucial. For Tumag, electrode production is not a separate preparatory step, but an essential part of the complete EDM process. By aligning design, production and application internally, we achieve:
- high dimensional and shape accuracy;
- reliable reproducibility;
- stable EDM performance;
- optimum surface quality;
This integrated approach is especially valuable for demanding applications in mould making, stamping tool manufacturing, precision mechanics, healthcare, high-tech and aeronautics & defence.
EDM3 graphite for stable performance
For our sinker EDM electrodes, we use high-quality EDM3 graphite, among other materials. This material is suitable for precision EDM thanks to its combination of electrical conductivity, thermal stability and predictable erosion behaviour.
Because graphite can be machined with very high precision, fine details, complex 3D shapes and sharp contours can also be produced reliably. This makes the material suitable for high-quality mould components and precision parts.
| Property | Benefit in the EDM process |
| Thermal stability | Limited deformation during the process |
| Fine machinability | High detail accuracy in the electrode |
| Predictable wear | Better process control and reproducibility |
Complete process control: from electrode design to sinker EDM
An important advantage of Tumag is that electrode design, electrode production and sinker EDM are carried out under one roof. Engineers, CNC programmers, HSM millers and EDM specialists work closely together to determine the right electrode geometry, EDM strategy and finishing level. For customers, this means less risk, a shorter lead time and a final product that better matches the technical specifications.
This approach offers clear benefits:
- Short lines of communication: technical coordination takes place directly between design, production and EDM.
- Fast optimisations: adjustments to electrodes can be implemented efficiently.
- Better process reliability: all steps are aligned with the desired final result.
- Consistent quality: each electrode is produced according to the same quality standard.
- Flexibility: suitable for prototypes, one-offs, complex components and critical mould parts.
Sinker EDM electrodes tailored to your application
No two sinker EDM projects are identical; the design depends on the geometry, the workpiece material, the desired roughness, the tolerances, the machining depth and the number of required EDM steps. Where necessary, we work with multiple electrodes for roughing, semi-finishing and finishing. This keeps the sinker EDM process stable and allows us to achieve the right balance between speed, accuracy and surface quality.
Tumag designs electrodes for, among other things:
- complex mould cavities;
- sharp ribs and fine details;
- deep or hard-to-reach shapes;
- precise technical recesses;
- precision mechanical components;
- machining operations in hardened or difficult-to-machine materials.
Sinker EDM electrodes with a direct link to practical application
Because Tumag not only produces electrodes but also uses them in the sinker EDM process itself, we know exactly what a good electrode must deliver. We incorporate this practical knowledge into the design, material selection and machining strategy.
This allows us to avoid unnecessary intermediate steps and provide electrodes that do exactly what they are meant to do: deliver precise, stable and repeatable EDM performance.
Do you have a complex EDM application or a mould component with critical details? Contact Tumag. We will be happy to assess which approach best suits your part.
Frequently asked questions about sinker EDM electrodes (FAQ)
Why does Tumag produce electrodes in-house?
By designing and producing sinker EDM electrodes in-house, Tumag retains control over the entire EDM process. This ensures short lines of communication, faster optimisations and consistent quality. In addition, the electrode and EDM strategy can be perfectly aligned.
Which materials are used for sinker EDM electrodes?
Tumag mainly uses high-quality graphite, including EDM3 graphite, for the production of sinker EDM electrodes. Depending on the application, copper or Elconite can also be used. Elconite, a tungsten-copper alloy, can for example be suitable when EDM machining carbide.
When is sinker EDM with graphite electrodes suitable?
Sinker EDM with graphite electrodes is suitable for complex shapes, deep cavities, sharp details and hard or difficult-to-machine materials. The technique is often used in mould making, precision mechanics and tool production, especially when critical tolerances and high process reliability are required.
Can Tumag also perform the complete EDM operation?
Yes. At Tumag, we perform all key EDM operations in-house: sinker EDM, wire EDM and EDM drilling. In addition, we also handle engineering, electrode production and quality control in-house. This allows us to coordinate complete EDM projects efficiently and carry them out with precision, from preparation to final inspection.
